Water in Engine

Replace the oil pump. I bougth a 71 Demon 340 years ago with the same problem. It had been left out in the open with no hood and no air cleaner. Drained about 5 gallons of water and some gunky oil. Put on a new filter and added some fresh oil and fired it right up. Oil pressure pegged, had a look at the new oil filter and it was like a very big metalic sausage - long and skinny. Shut that sucker down in a hurry!! Ended up having to jack the engine, drop the pan, and wiggle and grunt a new oil pump in there. I kept it for about 2 1/2 years after that and it always ran great. Not a recommended way to wash the engine. :)P